I'll go with Mahatma Gandhi on this one, "Be the change you want to see in the world." And the Buddha, "Hatred was never conquered by hatred, but only by Love." And Jesus, "Do unto others as you would have them do unto you," and "Love your enemy."
Properly understood, every religion, and also most athiesm, agnosticism, and our scientific society, all want peace and well-being for all. At the same time, extremists exist in every tradition. Let us live and teach the way of peace. Anything else, any effort to force others not to be extremist, is, itself a cause of extremism. People become extreme when they are forced by violence and violation. And, if they are killed, then that tragedy turns their families and friends into our enemies. Only by peace will we end extremism and violet conflict.